1. Field of the Invention
The present invention relates generally to a semiconductor module with vertically mounted semiconductor chip packages.
2. Description of the Related Art
A conventional semiconductor module, such as a memory module, is shown in FIG. 1. As shown in FIG. 1, a conventional semiconductor module 1200 may be composed of several semiconductor chip packages 1210 that may be mounted in a horizontal fashion on one or both flat faces of a module board 1230. The module board 1230 may have circuit patterns 1232 provided on the flat faces thereof and external contact terminals 1239 provided along one edge side thereof. For electrical connections to an external system, the packages 1210 may be electrically coupled to the external contact terminals 1239 through the circuit patterns 1232.
The conventional module 1200 configured with a horizontal mounting structure may have the limitations with regard to heat dissipation and mounting density. In a horizontal mounting structure, one flat surface of the package 1210 meets the flat face of the module board 1230, and the other flat surface is exposed to air. Thus, as heat is generated from the package 1210, heat removal by convection is made through only the outer flat surface. Therefore, the above-discussed conventional module may be susceptible to heat damage as the heat per volume rises. Further, due to a horizontal mounting structure, the conventional module may reach a mounting density limit.
In an effort to solve the above problems, a vertical mounting technique for mounting the packages on a module board has been introduced. A zigzag in-line package (ZIP) type is an example of a vertical mounting technique. The ZIP type may produce a desired effect on heat dissipation and mounting density, in a case where the module board supports only a few input/output (I/O) pins. However, the ZIP type is difficult to realize in module configuration having a substantial number of I/O pins.
An approach to overcome drawbacks of the ZIP type is to use a heat sink. FIG. 2 shows, in a cross-sectional view, a conventional semiconductor module using a heat sink. Referring to FIG. 2, a module 40 may have several semiconductor chip packages 10 vertically arranged and inserted at one end into respective sockets 32 provided on a module board 34. The module 40 may include a heat sink 36 provided above the packages 10, as shown in FIG. 2.
Each package 10 may be arranged on a corresponding circuit substrate 16, such as a printed circuit board (PCB), and may have a semiconductor chip 12 attached on one flat face of the substrate 16 through an adhesive 24. Connection paths 22 may be formed on the chip-attaching face of the substrate 16 and electrically coupled to the chip 12 through wires 26. The chip 12 and the wires 26 may be embedded in an encapsulant 28 for protection from the environment. A heat spreader 30 may be attached to the other flat face of the substrate 16 and may be bent at the top of the vertically mounted package 10, as shown in FIG. 2. The heat sink 36 may be provided across the heat spreaders 30 and attached thereto by an adhesive 38.
Due to the inclusion of a circuit substrate 16, the package 10 may realize many I/O pins. In addition, the heat sink 36 and the heat spreaders 30 may improve the heat-dissipating property of the module 40. However, a contact area between the packages 10 and the heat sink 36 may be insufficient, such that the heat-dissipating property of the module 40 may still not be satisfactory. Moreover, this type of module 40 may have drawbacks due to its relatively complicated structure and process of fabrication.